We have developed very sensitive and specific, two-monoclonal, antibody sandwich type assays for human thyrotropin, human luteinizing hormone (hLH), human chorionic gonadotropin (hCG), and human prolactin. Using the assays for hCG and hLH we have quantified hCG in unextracted blood of all normal non pregnant women, post-menopausal women, and men. Our data suggest hCG is secreted by the pituitary gland. and that hCG is secreted in pulsatile fashion in parallel with hLH in women. We now propose continued research in two broad areas: (A) continued technical assay development - for ACTH, human follicle stimulating hormone (hFSH), and human alpha chain, and (B) characterization of the "hCG-like" material secreted in normals. This includes the following: (1) characterization of the pulsatile dynamics and control of hCG in normal humans and humans with disorders of the hypothalamic-pituitary-gonadal system; (2) determination of the pituitary cell-type secreting hCG in normals; (3) physico-chemical characterization and determination of the amino acid sequence of hCG purified from pituitary, plasma and urine of normals; (4) physico-chemical characterization and determination of amino acid sequence of the "hCG-like material produced by bacteria with comparison to that produced by normal humans.